In the electronics industry, flexible substrates are quickly becoming popular as a base for electronic circuits. Flexible substrates can include a wide variety of materials including, for example, any of a myriad of plastics. Once a desired electronic component, circuit, or circuits are formed over a surface of the flexible substrate, the flexible substrate can be attached to a final product or incorporated into a further structure. Typical examples of such products or structures are active matrices on flat panel displays, RFID (radio-frequency identification) tags on various commercial products in retail stores, a variety of sensors, etc.
One major problem that arises, however, is stabilizing the flexible substrate during processing. For example, in a process of fabricating a thin film, a thin film transistors (TFTs) or thin film transistor circuits (TFT circuits) on a flexible substrate, a large number of process steps are performed during which the flexible substrate may be moved through several machines, ovens, cleaning steps, etc. To move a flexible substrate through such a process, the flexible substrate is typically temporarily mounted to some type of carrier substrate so that the flexible substrate can be moved between process steps.
However, the relatively high coefficient of thermal expansion (CTE) for flexible substrates compared to typical carrier substrates leads to significant CTE induced strain mismatch during temperature excursions of the TFT or TFT circuit processing. This phenomenon introduces significant distortion of the flexible substrate and can lead to handling errors, photolithographic alignment errors, and line/layer defects.
Therefore, a need exists in the art to develop novel compositions and methodologies for coupling a flexible substrate to a carrier substrate to mediate the preceding limitations.
For simplicity and clarity of illustration, the drawing figures illustrate the general manner of construction, and descriptions and details of well-known features and techniques may be omitted to avoid unnecessarily obscuring the invention. Additionally, elements in the drawing figures are not necessarily drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of embodiments of the present invention. The same reference numerals in different figures denote the same elements.
The terms “first,” “second,” “third,” “fourth,” and the like in the description and in the claims, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms “include,” and “have,” and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, device, or apparatus that comprises a list of elements is not necessarily limited to those elements, but may include other elements not expressly listed or inherent to such process, method, system, article, device, or apparatus.
The terms “left,” “right,” “front,” “back,” “top,” “bottom,” “over,” “under,” and the like in the description and in the claims, if any, are used for descriptive purposes and not necessarily for describing permanent relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the invention described herein are, for example, capable of operation in other orientations than those illustrated or otherwise described herein.
The terms “couple,” “coupled,” “couples,” “coupling,” and the like should be broadly understood and refer to connecting two or more elements or signals, electrically, mechanically, and/or otherwise. Two or more electrical elements may be electrically coupled, but not be mechanically coupled; two or more mechanical elements may be mechanically coupled but not be electrically coupled; two or more electrical elements may be mechanically coupled, but not be electrically coupled. Coupling (whether only mechanical, only electrical, etc.) may be for any length of time, e.g., permanent or semi-permanent or only for an instant.
The absence of the word “removably,” “removable,” and the like near the word “coupled,” and the like does not mean that the coupling, etc. in question is or is not removable.